The project for the Transboundary Aquifer System of the Northern Sahara (Algeria, Libya and Tunisia) has as its objective the protection of this critical resource, and in particular of the recharge areas and humid zones and ecosystems related to the aquifer. It includes two complementary components: (I) improving the knowledge of the aquifer and related ecosystems and (ii) implementing a consultation mechanism at the hydrogeologic basin level. In the three countries concerned - Algeria, Libya and Tunisia - the management of the NWSAS water resources will cover arid and semi-arid areas that are presently affected by desertification. Recent assessments have indicated the partly renewable nature of this aquifer, and hence the opportunity for its sustainable management, which would necessarily include the protection of water quality (recharge areas) and of humid zones, such as oasis, shebkas etc, which are critical from the socio-economic and environmental points of view. The project represents a significant first step in this direction taken by the three countries.

THE NWSAS PHASE II: OBJECTIVES AND PROGRAM

The gotten results during the phase I permitted a strong capitalization of information and instituted a real dynamic of exchange between countries, resulting notably in a consensual process on the resources exploitation and the development durability in the basin.

However, the scale to which has been achieved the model, the allocated budget and the distributed time didn't permit to take in charge necessarily bound uncertainties to a survey of such span as well as the extra-hydraulic data in view to elaborate an integrated management at the scale of the basin. This is how the necessity to complete the survey imposed itself and whose program ensues:

• recommendation of technical and scientific committee, notably complementary studies concerning hydraulic aspect in order to consolidate the knowledge on the NWSAS;
  
• requests and recommendation from the countries and cooperation partners for the integration of socio economic and environmental data

It is on these bases that have been conceived the Phase II of the NWSAS project whose activities include six components (or Work Packages WP) as represented by the logical frame of the figure 3:

• WP10000-Hydraulic Component: activities of this component have for objective to perfect knowledge of the NWSAS while perfecting uncertainties raised during the phase I and then to improve the reliability of elaborate simulation results.
  
  
• WP20000-Socio-economic Component: the foreseen activities will have for result to complete the hydraulic result analysis, to value the actual situation, notably on the agricultural plan and to clear recommendations.
  
  
• WP30000-Environmental Component: it has for objective to identify all sources susceptible to weaken the resource and ecosystems.
  
  
• WP40000-information System Component: the objective is to strengthen acquirements of phase I while integrating data other than hydraulic and to define administration and anchorage modes of the information system as well as the project Steering Committee and cooperation partners according to the specific modalities.
  
  
• WP50000-Consultation Mechanism Component: results of the four previous components will come to reinforce the main activity and at the same time the final objective of the project that represents the Consultation Mechanism.
  
  
• WP60000-Monitoring-evaluation Component: this component will be assured by the OSS concerning the administrative management of the project.

The NWSAS phase II is financed by three cooperation partners:

• DDC-SWISS
• FEM-PNUE
• FFEM-FRANCE

The NWSAS program its initial phase (phaseI July1999 - December 2002) was aiming two objectives:

1. The development of a complete survey on the NWSAS water resources, that includes:
   • an integrated information system common to the three countries;
   • a numeric model of management whose scenarios are based on the horizon on the socioeconomic data of the year 2050.
     
     
2. The setting up of a Consultation Mechanism aiming to:
   • reinforce the consultation between the three countries;
   • to cause the reflection on the durability of this resource and the optimization of its exploitation in link with transfers inter-generations and the struggle against the desertification;
   • an actualization of the resource balance and the definition of an optimal scenario of abstraction on the horizon 2050, through a management numeric model
   • a permanent device of compilation, treatment and information management
   • procedures of information exchanges inter-country.

The NWSAS phase I programme, July 1999 - December 2002 was the object of a financing from the three cooperation partners : DDC Swiss - IFAD - FAO

At the end of this phase, was elaborated an integrated information system composed of:

• a system of assistance to the management of the Septentrional Sahara water (SAGESSE), that is a tool of assistance to the decision
• a common data base coming from the three countries and listing more than 7000 water points spread out through the basin.
• a Geographical Information System with geo-referenced data
• a multi-layered model at the basin scale permit:
  • to define exploitation scenarios at horizon 2050
  • to deepen the knowledge on the basin and define the complementary studies to improve the knowledge.
  • to identify the risks and determine the most vulnerable areas.

In parallel to the model, the project perfected a micro-model, a tool of which the simplicity and the instantaneity of global results are less complicated that the model's, which permit to arrange exercises meeting that ended in a consensus as to the resource protection and also to consensual scenarios.